This invention relates generally to sealing arrangements for pool gateways, and more particularly to removable seals for use between adjoining pools in a nuclear facility.
Nuclear facilities include pools for the storage and service of irradiated components. In such pools the components are submerged in water or other liquids to provide radiation shielding and cooling. These pools are often interconnected through a series of gateways to enable underwater transfer of the irradiated components. The interconnecting gateways also serve to minimize crane clearances required to move components between pools, allowing them to be moved through a gateway rather than over a pool wall.
The liquid level in each of these interconnected pools must be adjusted periodically in accordance with the particular activity taking place. For example, a pool region above a reactor and an adjoining fuel pool typically are both filled with water or other effective liquid during the transfer of fuel; however, the level of liquid in the reactor pool region typically is lowered to provide for subsequent reactor maintenance, while the liquid in the fuel pool usually is kept at the higher level. To accommodate variant liquid levels in adjoining pools a barrier or seal for liquids is required in the interconnecting gateway.
The required seal must be removable to retain the capacity for underwater transfer of irradiated components between pools. The seal also must be capable of remote actuation when submerged. Furthermore, the seal must include minimal permanent pool attachments which might otherwise interfere with operations or adversely affect crane clearances.
In certain nuclear facilities, hinged gates have been used as gateway seals. However, hinged gates are impractical for many applications where the clearance requirements for the sweep of the hinged gates would seriously detract from the useful space of a respective pool. Other nuclear facilities have employed keyed shielding blocks removably stacked in gateways to act as barriers between interconnectable pools. These blocks provide satisfactory radiation shielding from irradiated components contained in the pools. However, the mating surfaces of the keyed blocks usually provide undesirable liquid leakage paths between the adjoining pools.
Removable gates employing inflatable tubes positioned about their peripheries have also been used in the past. However, their effectiveness when used in U-shaped, or open-top gateways, such as those common in nuclear facilities is reduced because the U-shaped design provides no means to restrain the vertical movement of the liquid barrier in reaction to the expansive force of the inflatable sealing tube acting against its lower edge. Thus the expansive force of the tube useful in forming a seal between the lower portion of the gate and an associated portion of the gateway is disadvantageously spent raising the frame.
Accordingly, it is an object of the present invention to provide a new and improved gateway seal between adjoining pools in a nuclear facility.
Another object of the present invention is to provide a sealing device which is removably positionable in a gateway and includes remotely actuatable restraining means to enhance the seal between the sealing device and gateway.
Still another object of the present invention is to provide a sealing device for use in a U-shaped gateway between interconnectable pools in a nuclear facility which includes an inflatable sealing member the expansive forces of which are counteracted on all three sides to provide an enhanced seal between the sealing arrangement and gateway.